Harvia's wood-burning stoves for large saunas
P.08Commercial
Pro 20 / Pro 36 (WK-series)
Specs from harvia.com and Harvia Plc materials, in US units. Check the current Harvia manual before you wire or install.
31 kW of wood-fired output for rooms up to 1,270 cu ft, built in Finland for large saunas.
Pro 20 (WKPR20M) and Pro 36 (WKPR36M) are Harvia's wood-burning stoves for large saunas. Pro 36 is the headline unit: 31 kW of rated heat output, rooms of 494 to 1,270 cubic feet, up to 132 lbs of stones, and a fire chamber that accepts firewood up to 15.3 inches long. Harvia lists a 4.1-foot ceiling safety distance above the 32-inch-tall stove, which works out to a ceiling of about 81 inches.
Commercial and destination wood-fired saunas, ski-town communal bathhouses, Nordic-inspired resort installs, large private cabin builds where the operator wants the Finnish commercial experience. Rooms 500+ cu ft with 81+ inch ceilings.
Editorial analysis for context, not a purchase recommendation.
Room sizes in cubic feet, stone loads in pounds.
From earnings calls, investor presentations, annual reports, and the Harvia catalog.
“Muurame factory, the world's largest heater and sauna component factory: over 150,000 heaters per year.”
Harvia Capital Markets Day 2024 presentation
Pro 20 and Pro 36 are produced at Harvia's Muurame, Finland factory alongside the rest of the wood-burning heater line
“In 2023, manufacturing [of wood-burning heaters] was almost fully moved to Muurame.”
Harvia Plc 2023 Annual Report
After Harvia's 2022 exit from Russia, its wood-burning heater production was reshored to Finland; Harvia's product data lists the Pro 20 and Pro 36 as built in Muurame
Check each note against the current Harvia manual and your local code.
N.01
Harvia lists a 4.1-foot ceiling safety distance for the Pro 36 and 4.27 feet for the Pro 20. Add the stove heights, about 32 and 30 inches, and both need a ceiling of roughly 81 inches, more if the adjustable legs are raised. Harvia's product pages also list a 6.56-foot room minimum height, but the ceiling safety distance is the tighter limit.
N.02
Harvia rates the Pro 36 at 31 kW for 494 to 1,270 cubic feet, with up to 132 lbs of stones. The Legend 240 SL is rated at 21 kW for 353 to 848 cubic feet, carries about 441 lbs of stones, and is built to be fired from another room or from outside the building. The choice comes down to room volume and whether the fire should be tended from outside the hot room.
N.03
Harvia's declaration of performance lists a flue gas temperature of about 850°F for the Pro 36 at its rated 31 kW, and the stove reached about 1,150°F in the EN 15821 safety test. Harvia specifies a chimney rated to temperature class T600 and a 4.5-inch (115 mm) connection. Have a qualified installer match the chimney system to those figures and to local code.
N.04
Harvia's manual says the stones break down from the temperature swings and should be rearranged at least once a year, more often if the sauna is in frequent use, removing fragments and replacing disintegrated stones. A commercial room that runs all day sits at the frequent-use end of that guidance.
Product, detail, and technical images from the Harvia Media Bank.
Images: Harvia Media Bank, courtesy of Harvia Plc, unless the caption says otherwise.
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Product data comes from Harvia Plc investor materials, earnings call transcripts, harvia.com, and harviagroup.com. Quotes carry their source where a public one exists. SaunaNews is not affiliated with Harvia Plc; this page is a product record for news coverage, not a sales page. Spot an error or an outdated spec? Tell the newsroom .
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